Hospital Patient-Care and Outside-the-Hospital Energy Profiles for Diagnostic X-Ray Imaging

Purpose: to assist the radiology community with new ways to improve hospital sustainability and energy reduction programs of their healthcare organization, to explore the hidden public health impacts (beyond the success in radiation reduction), and to aid in the maintenance of certification with data on departmental quality improvement initiatives. Method: The study followed a standard life cycle assessment protocol to measure energy from a diagnostic x-ray exam then expanding the study to all hospital electrical energy related to x-ray department usage. In addition, all the fuel energy used to generate electricity and to manufacture x-ray consumables were measured to quantify the hidden public health effects. Results: The in-hospital energy use for a single x-ray diagnostic image is in the range of 0.49 to 0.74 kWh per x-ray image (2.25 to 3.24 kWh per patient) for the x-ray scanners, ancillary devices, and lighting fixtures. The out-of-hospital energy consumption (fuel for generation and transmission of electricity for the hospital plus energy to manufacture the disposables consumables and reusable textiles) is about 300% larger (in the range of 1.54 to 2.11 kWh per image (7.08 to 9.28 kWh per patient). The CO2eq for the entire x-ray service on a per patient basis is 2.0 to 2.7 kg CO2eq per-patient. Conclusion: The transparent, detailed life cycle approach allows the data from this study to be used by radiologists to examine details of direct and unseen energy impacts of x-ray diagnostic images for patients (not radiation-related). The actual active patient scan energy that produces the x-ray images is only about 0.3% of the total life cycle energy. There are some environmental differences between these two x-ray machines, but not substantial. With seven substantial parameters that determine the overall energy consumption, it is expected that the patient x-ray images can be delivered at lower in-hospital and outside the hospital areas. The patient utilization rate and the idle energy of the x-ray and ancillary devices may offer alternatives to improve the environmental footprint of patient x-rays. With 600 million annual U.S. x-ray images, the public health impacts on society's public health are now measured in this paper.